Waste-to-Energy
Addressing the Conflicting Priorities of Waste Reduction and Energy Development
Optimize to recover maximum value rather than maximum energy.
Walker Larsen
Many valuable materials are currently being discarded rather than used productively, and more needs to be done to maximize the value we recover from material streams. Unfortunately, building energy recovery facilities to handle the existing waste load creates a requirement to continue generating the same amount of waste, creating potential problems for plans to reduce waste. Waste is the fuel for the energy facility, and an energy facility built to a specific capacity will need a specific amount of fuel to meet that capacity.
However, waste is wasteful. Waste is the result of process inefficiencies or inefficient use of materials between different processes. It is not a renewable resource, and as we begin to use materials more efficiently and to reuse more materials in different processes, there will be less material in the waste stream.
This article considers how to both productively reduce waste and safely recover energy when these two activities are planned strategically as part of a larger materials management system that carefully considers overall system capacity.
Key Points
First, the existing system is unsustainable. In many cases we are generating more waste, not less, and recycling rates are generally flat or increasing too slowly. Despite some innovative and effective efforts to reduce waste and increase recycling in some locations, in general the U.S. is still moving a very significant amount of material to landfills. According to the US EPA’s Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2008, despite improvements in the national recycling rate, we still move 54 percent of our discarded materials to landfills.
Second, the current waste stream contains problematic materials but also contains valuable commodities. While there are materials in the waste stream that may cause harm to humans and the environment if not handled properly, there are also many materials that may be put to productive uses. The EPA’s 2008 Facts and Figures data also indicates about 64 percent of discarded material may be reusable or recyclable. This includes rubber, leather, textiles, plastics, metals, glass and paper, although it may not be currently possible or economical to reuse or recycle some materials, and some materials may be too contaminated by organic matter like unwashed food containers or greasy pizza boxes. Additionally, about 32 percent of MSW is organic material (not including soiled paper products) which can be the input for energy generating facilities.
Third, streamlined and revised regulations and policies are necessary to allow and create market activity. Innovative, entrepreneurial people have long sought ways to reuse materials that others throw away. These materials can become cheap inputs to processes that add a lot of value and end up creating savings for waste management and revenue from new products. However, using waste can be problematic and difficult because of the rules associated with the reuse of materials that have entered the waste stream. New and revised rules that recognize the potential value of common material streams and allow for safe reuse are necessary to fully stimulate new material markets.
Lastly, recovering energy from waste can be productive and clean, but Energy-from-Waste (EfW)processes that use mixed MSW (plastics and organics) should not be eligible for renewable energy incentives. These incentives are designed to promote and maximize energy generation and do not consider waste reduction or materials management goals. More importantly, broadly speaking, mixed waste is not a renewable resource since it can contain inorganic material such as petroleum-derived plastics.
System Capacity
The most critical issue is the material handling capacity of energy from waste facilities relative to the amount of discarded material in a given area. This capacity can be thought of in two ways, which reflects the dual roles of an EfW facility. First, the facility is built to safely process a specific amount of waste, which is important in terms of regional waste management considerations. Second, the facility is built to generate a specific amount of power based on a specific requirement for fuel, which is important in terms of regional power generation. Being able to accurately predict the inputs and outputs for the facility is critical for regional waste management and energy development planning; cities and towns need to know there is a place to send their waste, and heat and power users need to know how much heat and electricity is available to meet their needs.
A facility is built to process a specific amount of material and generate a specific amount of energy. These input and output levels need to be maintained over the operating life of the facility in order for it to remain economical. Once the facility is built, it requires the same amount of input material for many years. Therefore, overbuilding capacity could result in long lasting materials management problems. The essential point is that overall system capacity must be carefully considered in order to optimize both material recovery and energy recovery.
Changing the System
Simply put we need a combination of appropriate regulations, collaborative regional planning and local permitting, and targeted market incentives. The ultimate goal is to facilitate markets for materials, as production inputs or fuels.
Alternative Energy Incentives
New facilities, whether for sorting and processing materials, for new markets or recovering energy, require significant capital investments. It is costly and complicated to sort and process mixed waste streams. Businesses will focus on building energy facilities if the available incentives are based on energy generation. Energy-from-waste facilities should be eligible for separate alternative energy incentives that emphasize material reuse and recycling over energy production. Basing incentives on the amount of energy produced (as is the case with renewable energy credits) encourages facilities to maximize energy output and convert as much material as possible to energy. This is one important reason renewable energy incentives are not appropriate for EfW facilities. An alternative incentive system could provide payments based on a combination of facility conversion efficiency and upfront material reuse/recycling to instead encourage the more efficient use of less material as fuel, and reward creative reuse and recycling.
Appropriate Regulations
It is currently possible to put some materials to productive use before they become waste, but once a material is mixed into the waste stream it becomes very difficult to put it to productive use. This creates an incentive to reuse valuable materials instead of discarding them and this structure should remain in place to continue to facilitate innovative material markets that operate between production and disposal. However, rules and regulations for discarded materials should also allow for some productive use “behind the trash can.” Rules need to provide opportunities to businesses that can safely put mixed waste materials to productive use. This may mean recovering certain material streams for reuse and recycling opportunities. This may also mean using certain material streams for fuel for power plants. A clear regulatory path will allow productive material markets to flourish.
Regional Planning and Local Permitting
Waste is generated locally, but is a truly regional issue. The economics of disposal, which to some extent are a reflection of space constraints and surpluses, dictate where waste is ultimately disposed. This creates a tricky situation, because we need to allow for continued cost-effective waste management of our entire waste stream while simultaneously seeking to fundamentally change the way we manage discarded materials.
Counties and states should work together to develop regional materials management plans. These plans should prioritize the construction of materials management facilities that are capable of processing an amount of material that is consistent with regional waste reduction goals. For example, if a region wants to reduce its waste from 15,000 tons per day (tpd) to 8,000 tpd, it should seek to permit facilities that can process up to 8,000 tpd, not more. These plans should include rules that seek to streamline local permitting processes for appropriately sited facilities that employ appropriate technologies to safely and productively manage materials and recover energy. In other words, materials management planning should essentially develop regional system plans similar to those used by the regional system operators of the electric grid.
A Singular System
Conflicts between waste reduction and energy recovery priorities are extremely complex and cannot be adequately addressed by this short article alone. A lot of good work is already being done to facilitate new materials markets and creative reuse opportunities. At the same time, technologies to recover energy from waste are becoming more sophisticated, and, if deployed appropriately, will likely provide significant benefits to society. Ultimately, most importantly, we need to move away from the system that makes it cheap and easy to bury valuable material in the ground. If we focus on waste management and energy development as a singular system with unified goals, rather than separate systems with separate goals, we can design a system that promotes both waste reduction and energy development.
Walker Larsen is a Project Specialist with CLF Ventures, Inc., the Boston, MA-based non-profit consulting affiliate of the Conservation Law Foundation. CLF Ventures works with clients to implement strategies for sustainable change. He received a Master of City Planning from the Massachusetts Institute of Technology and brings an environmental planning perspective to the waste management and energy development discussion. He can be reached at 617-850-1709 or via email at [email protected].